Process of treating ores containing irom



' Sept. 8, 1925.

w. WESCOTT PROCESS OF TREATINGORBS CONTAINING IRON Filed July 14. 1922mum Hot Patented 8, I925.-

. 1,551,186 UNITED STATES" PATENT- Torr-lea.

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BOSTON, IABSAOHUSE'I'TS, A CORPORATION rnocnss or 'rnn arme on! commutemom r Application fled July 14,103.} m1 10.114385.

To all whom it may concern:

Be it known that I, Enmzs'r W. Wnsoorr,

a citizen of the United States, residing at Niagara Falls, in the countyof Niagara and 6 State of New York, have inventedcertain new anduseful-Improvements in Processes of Treatin Ores Containing Iron, ofwhich the following is a specification.

This invention relates to processes of 10 treating ores containing iron;and it comprises a method of separating and recovering iron oxid, as inutilizing lean iron ores, purifying bauxite, sand, etc., treatingcomplex oresv containing iron oxid as well as other values, etc.,wherein the ore or'material is treated with chlorin in the presence of areducing agent to produce and volatilize ferric chlorid away fromresidual solids, the ferric chlorid is oxidized in vapor form withoxygen (air) to produce chlorin and iron the treatmentof.,more'material; all as morefully hereinafter set forth and asclaimed.

" It isrthe purpose of the present invention to provide a ready,economical and efiicient method of removin or recovering iron oxid,useful in many re ations, as in producing iron oxid in a-concentratedform from lean iron ores (enriching iron ores), in treating iron orescontaining, in addition to iron oxid,

various other values, in purifying bauxite intended for making aluminumpreparations and aluminum, in purifying glass sands, etc. To this end,advanta e 18 taken of 'the ready interconvert-ibility o ferric oxidandferric chlorid, the iron oxid of the ore or material being va orizcd andremoved as ferric chlorid w1th the aid of chlorin and the fer-.

ric chlorid burnt with oxygen (air) to re- 40 gain .the chlorin andrecover the iron oxid.-.

' The chlorin used in the process is, so to speak, merely a carryingagent for the iron oxid and is not lost but used repeatedly in a cyclicmanner. Incidental'losses of chlorin are generally quite small, and verylittle is needed for re lenishing or make-up addi tionsj That, use forthe stock and for makeup additions may be from any suitable source, suchas electrolytic chlorin, Deacon chlorin commerci'al liquid chlorin,etc.-

In practical embodiments of my invention,

, the ore'or material is treated with-chlorin in the presence of areducing bodylittle oxid and left behind.

the gangue are left greater or less propor-' and the chlorin is returnedto serve in waste reactive with either chlorin or iron, such as carbonor producer gas at a temperature sufiicient to form and volatilizeferric chlorid formed in the treatment, thevapors being led from thereaction chamber for disposition elsewhere. The gan e is freed of iron Wdih some ores, with tions of relatively non-volatile heavy metalchlorids. When present some proportion of these chloride may goforwardwith the ferric chlorid vapors,- from which they are readilseparated. In either event they may orm a valuable by-product. Theremoval of iron from the material. may be made as complete as may'bedesirable or economically feasible. Such fixed chlorids as remain in thegen e are readily available and may be remove by leaching with water oran appropriate solvent. I

In order to regain the chlorin for re-use and to reproduce the ironoxichthe ferric chlorid in the form of vapor is burntwith oxygen (air).chlorid in the vapor form exposed to the action of oxygen or air at atemperature around 700 to 800 C. is easily converted into ferric oxidand free chlorin. The reaction is smooth and complete and is rapid attemperatures around 800 C. The iron is oxidized and the chlorin setfree. B the use of a slight excess of ferric chlori the utilization ofthe oxygen may be quantitative, or practicall so, giving a practicallypure chlorin whi e with the use of a slight excess of air, all theferric chlorid is converted into. ferric oxid. By proper proportioni ofthe volume of air and of ferric chlor i mixture of nitrogen and chlorincontaining 30 per cent or so of chlorin, a gas mixture very well adaptedfor use in the first step of the process.

In most embodiments of my process and 'in the embodiment at presentpreferred by me, I cool and condense the vapors of ferric chlorid comingfrom the reactlon vesse prior toperformin the stated oxidat on, therebygetting ri of the accompanym 1 which are mainl nitrogen an carbon oxids. Any volati e non-metallic chlorids (sulfur, phosphorus,' arsen1c,etc.) which may be present in the mixture coming it is practicable toproduce a hot As I have found, ferric 'from the reaction chamber goforward with .metal chlorids w ich may have one forward therewith.There'is genera y also a certain amount of ore dust carried forward fromthe reaction vessel, although this may be, to a great extent, separatedby leading the hot vapors through a suitable settling chamberon theirway to the condenser. As I usually practice the process, aftercondensing the ferric chlorid I reheat it to vaporize it, leavin behindthe ore dust and such other metal ic chlorids as may be present. Thevapors are quite pure, even in the case ofv ery 1m ure ores. The ferricchlorid vapors are le into a suitable oxidizin chamber, which is bestrather roomy, an

are burnt with air at a temperature around 800 C. The particulardimensions and type of chamber depend to some extent upon the physicalform of iron oxid desired. The iron oxid formed settles out and isrecovered and removed in any suitable way. It

' may] come down in a crystalline form or as very fine pulverulentmaterial, according to conditions. In a general way, it may be said thatthe greater the time ofiered, that is, the greater the time during which.matey is nerally ve it E? rials remain at a high temperature, the

coarser and more easily settled is the "iron,

- 3; oxid. As a general rule,-I find it better to so adjustconditionsthat the gases shall remain at the reaction temperature 8 to 12 seconds,in recovering the oxid for metal pprposes and as afiller for rub eretc., etc. highly e air used-in oxidizin should be preheated, the amount0 preheat necessary of, course depending somewhat on the heat .theairishould be at 1050 C. to give the deavailablein the ferric chloridvapors. 'If

the ferric chlorid vapors are at, say, 350? C sired temperature of about800 C. in the oxidation chamber. With oxygen or en-' riched air, thetemperature conditions are somewhat ,diflerent; and their use offersmany advantages where they are. available. With air, I' generally employslightly more than the volume theoretically necessary, giving me an,efliuentgas containin ."about 30 per cent of chlorin by 'volinne,'t erest being nitrogen, etc. Usm oxygenin the right amount, a substantia ypara chlorincan be made. l In the described process, the remnce ofmoisture is undesirable, as lea ing'to the formation of HCl and loss ofchlorin; and

while this loss may be obviated to a greater or less extent by variousexpedients, I find it better to operate with my materials (ore, carbonand air) as dry and free of moisture or hydrogen as possible. In most ofthe embodiments of myinvention, I therefore heat the ore or material tobe treated prior to chlorination, sufiiciently to remove moisture, freeor combined. Iron oxid itself is readily dried but accompanyingminerals, such as alumina and bauxite, are often somewhat more diificultto dehydrate. In dehydration, in a measure,'time and temperature arereciprocal. The dry material is next mixed with a little carbon, to takecare of the 0 gen of the Fe,O,. It is desirable to use co e, anthraciteor charcoal as free of volatiles. as possible. The carbon is alsoadvantageously preheated. It is not desirable to use more carbon thancorresponds to a proximately 12 or 13 er cent of the Fe,& present. Ifdesired, t e ore and the carbon ma be heated together to produce apartia reactionprior to intro ucin chlorin. Or the ore may beartiallydeoxi ized with producer gas simu taneously with, or subsequent to,drying. The ore, re-reduced or not is next, contacted 'with c lorincoming from a later stage in the operation and. at a relatively hightemperature. x

Th "temperature required in the chlorination operation is not high,being around 400-450 0.; nor is any great volume of heat necessary, therequirements of course, varying with the design of apparatus, the amountof radiation loss, etc. 11 a general way, with apparatus of sufiicientsize to give a small radiation loss and with properypreheated gases andmaterials rich in iron oxid, the reaction is, or may be, selffrom anexternal source, but this is inconvenient and is better avoided. By aprereduction of the material, iving a certain amount of metallic iron ore0, the action .supporting. The apparatus maybe heated of the chlorinbecomes highly exothermic and where much heat is required in thereaction apparatus, it iscommonly most convenient'to develop it in thisway: b a prereduction as well as by pre-heating 0; the ore to betreated. In the reaction, the carbon sresentis. nearly 0,, but a smalordmaril formed, an this fact contributes to the t ermal economy of theprocess.

entirely converted into pro ortion of CO being' Ordinarily, I work withthe material reducedto a finely powdered-condition and reduce throughcontact by the use of some cm of rotary drum or kiln. It is convenienta) feed the powdered material in counter-current against the chlorine ina slightly inclinedkilmi which is best shoul dered in order to preservea substantial bed gen mixture from alater stage oithe operaof materialtherein. Where a chlorin-nitro-- 3 tion at a temperature of 7 -800 C. isemmaterials, .very little chlorin goes forward with the efiluent gasesand vapors, either as such or as HCl. The eflluent gases and vapors maycarr chlorids in small amountr For example, in the presence of nickel,some amount of nickel chlorid goes forward with the ferric chlorid. Thesame is true of cobalt, copper, silver, etc. Sulfur and phosphorus arealso volatilized to some extent. On cooling the efiluen't gases andvapors down to, say, 100 or 150 C., the ferric chlorid is condensed andwith it any other heavy metal chlorid .which may be present. Theuncondensed gases and vapors go forward to a suitable scrubbing system,if it be desirable to recover sulfur or phosphorus. If the gases be notscrubbed, their heat may be utilized in assisting in dehydrating theore. If, for any reason, it be desirable to so conduct the operationthat an excess of chlorin is present, this may be removed by adsorptionin charcoal, coke or the like; the charged carbon being afterwardsreturned to the system in the chlorinating stage.v v I,

The condensed ferric chlorid, together with some ore, dust, istransferred from the condensing arrangement to a vaporizer wherein it isheated. The ferric chlorid volatilizes, leavingbehindi it any, othermetal chlorids, such as silver chlorid, nickel chlorid, etc., which maybe present and also the ore dust which may have gone forward with theyapors. The solid residue may be treated 111 any desired way to extractvalues present; If it contains much iron or ferric chlorid, it mtay goback into the system for retreatmen It is commonly convenient to run asmall stream of air or'chlor-in through the volatilizin chamber, part1to assist in the volatilization of the ferric chlorid and can it forwardand partly to maintain an 0x1- dizing atmosphere to prevent theformation of ferrous chlorid, The volatilizer can be made of iron andoperated at an external temperature of 400425 (3., the iron beingrotected by the formation of an adherent ense coating of ferrouschlorid. However, certainother and more resistant metals of the natureof alloys can be used to advantage. In a general way in ferrous alloysthe presence of any othermetal, such as chromium, nickel, cobalt, etc,givin chlorids less volatile than ferric chlorid, in-

creases the resistivity of iron. The vapors coming from the volatilizermay be passed through a superheater prior to-their entersome other heavymetallicing into the combustion chamber proper. The superheater may bemade of the special alloys mentioned, or of ceramic 'materials. It isdesirable to have the ferric chlorid vapors enter the combustion chamberat a temperature between 400 and 500 C. The combustion chamber itselfmay be a 'cylindrical tower and brick built, the gases enterintangentially at a mid-point. It is well to eat insulate this chamber.

As will be obvious, the foregoing process can be used for removing theiron from clays and sands to fit them for ceramic urposes. It may beused'for purifying auxite to free it of iron. I, however, re-

gard it as more particularly applicable to materials richer in iron,such as 1ron ores certain pyrites cinders. These cinders may,

and often do, contain copper, nickel or cobalt or all three inproportions rendering the use of the present process desirable. One suchcinder available, for example, carries 60 per cent iron, 1 per centcobalt, 0.3 per cent nickel and 3 per cent copper together withconsiderable sulfur. present method the sulfur is largely removed andthe copper, nickel and cobalt are recovered in a desirable form, aschilorid. It may be noted in this-connection, however, that the moresulfur is resent in the material treated, the greater IS the loss ofchlorin.

I shall, however, describe my process more particularly with regard tothe treatment of certainCuban iron ores. Similar ores are found in otherparts of the world, notably in Greece and in New Caledonia. These orescarry 40 to' 50 per cent iron but they also carry considerable alumina,which introduces fluxing difiiculties in the blast furnace. They alsocontain a small amount of nickel and some chromite, both of which areworth recovering while neither is desirable in an ore used to makemerchant iron. In beneficiating these ores b the present invention, theore is dehydrate and powdered. Drying is advantageously done in a rotarykiln of some type. Comminution is advantageously quite fine, often sothat to 98 per cent shall pass through a lOO-meshsieve. The degree of'comminution necessary depends however greatly on the size of themineral grains and upon the amount of gangue in the mineral treated. Thefiner the grinding, the more rapid the chlorination but in each case alimit must be set'by consideration of the cost of grinding and ofrehandling excessive dust, as against increased kiln capacity. The oreis then mixed with a littl fine carbon. Or it may be reduced withproducer gas. The hot reduced ore, or a hot mixture, of ore and carbon,is

placed. in a rotary agitating drum or kiln By the maintained at atemperature of about 450 C. at the ore entrance end. Outside heat may beemployed but is in general not necessary. Over and through the ore istransmitted a hot mixture-of nitro en and chlorin coming from a lateroperation. The iron oxid is volatilized as ferric chlorid. With itgenerally goes some or all of the nickel present. The residue, afterchlorination, contains the gangue. Any contained nickel chlorid, can beextracted by leaching. It also contains more or less chromite, which canbe separated and recovered by gravital recovery methods, such asshakingtables. The vapors of ferric chlorid, carrying some ore dust andsome nickel chlorid, pass into acondenser, where the ferric chlorid isdeposited. Sulfur chlorid, etc., for the most .part pass on uncondensed.The ferric chlorid is next heated to a temperature above.

350 and vaporizes, leaving behind item dust contaimng some nickelchlorid. nickel chlorid is-recovered by leaching." The vaporized ferricchlorid is burnt with hot air, as previously described, giving thechlorin-mtrogen mixtureused in the first stages of theo eration. I

Instead of c lorin, in thepresent invention I may use bromin,volatilizin theoxid of iron as ferric bromid, burning t e bromid toreproduce bromin and iron oxid, andreturning the bromin .to the systemfor use anew. This 'procedureoifers some advantages and because of theeconomy of halogen possible in the present process, the use of.

bromin is practicable. Wherever I f have mentioned chlorin, therefore, Iwish it to be understood that I may use bromin in its lieu.

In the accompanying illustration, I have shown more or lessdiagrammatically, cer-. tain types of apparatus useful in the presentinvention The view is partly in elevation and partly in central,vertical, longitudinal section. 4 1

In this showing, element --1 is a hopper supplying iron ore or the liketo conveyor mechanism 2, this ore having been previously heated:orpartially reduced by means not shown. The ore is taken forward by theconveyor and delivered into a; rotary inclined kiln-like structure 3provided with shouldered ends 4 andb. This kiln turns on rollers 6 andis actuated by suitable mechae nism 7. As shown, it hasa metal casing 8condenseF13; As shown,

lined with brick or ceramic composition. 9. Atflthe 11 per or feedend,it abuts against .a ang insulated. At the other or lower end, it

' abuts against the gangue receptacle 11 in a similar manner. The ganguereceptacle is provided with gate 12 for removing solids- The vapors' offerric.

om time. to time. chlorid pass through-the va or conduit intois'oondenser 1s vertical and is provided with internal con- .leailets.With proper re vapor conduit 10 suitably heat.

veyor or wall scraping tuated from a source 0 power (not shown) 'bymeans 15., At-the bottom, it is stepped in spider 16. Uncondensed vaporsand gases pass to a place of disposition, 'not shown, through-conduit 17As already stated, this conduit may, if desired, communicate withcondensing and scrubbing means for removal Thei condensedi ferricchlorid drops through conduit 18 and vapor seal-not shown into a varizer. As shown, this vaporizer comprlses'a tubular metal conduit 19containing conveyor 20. The conduit andconveyor may be made, as noted,of iron or of a more resistant alloy, such as a chrome-iron alloy.External heat is afforded by heatingjcasing 21 receiving fire gases orthe like at 22, the heat- .ing medium passi-n to exitat 23. The casi'ngis provided wit pyrometer 24 for indicatin temperatures.

alved inlet 25 is provide .for introducing a modicum of air or air andchlorin to assist in vaporizin the chlorid and preventing reduction. Attimes, more or less coke dust passes. forward with the ferric chloridand may here,eaiercise a reducing action. The ore .(lust and fixedchloridsgstripped of ferric chlorid, aresent :to a's'liitable place ofdisposition through outlet 26,- rovided with gate 27. Vapors of ducedfsettles to the bottom and is removed at outlet 31 from tinieto time orcont-inuously. With. the particular type of chamber shown, other thingsbeing equal, the finess of the oxid settling depends, in a measure, uponthe dimensions and internal contour of the chamber, theseafi'ecting thetimeofl'ered the iron oxid to or stallze. Where well caivstalizedvmaterial is obtained, the parmechanism 14 ac-- "015; Phosphorus chlorid,sulfur chlorid, etc.

ticles are generally more or less micaceous;

they tend to be in, the form of thin, flattened lation between the prortions of erric c 'lorid vapors entering m 28' and air from-30,-and withproper control of temperatures, etc., the reaction betweenthe O, of theair and the Y FeOl is smoothand practically quantitative. Ordinarily, Iso re late condltions as to obtain a mixture 0 chlorin'and nitrogen,

etc., carrying about 30 per cent of chlorin by volume and at a temerature of 700 to 80\O whereiferric c lorid can be obtained, myinvention is susceptible of use in producing pure chlorin orchlorin-contain ng gases for general purposes. However, for the presentpur oses, I 'am-descrlbing my invention as embo ied in the production offerric chlorid from iron ore and the like,

reproduction of the chlorin used therefor,-

, 19 and combustion chamber 29.

In addition to the iron ores, etc, recited, the present process isapplicable to. various concentrates and ores. The well known coppernickel ores of the Sudbury-district of Canada, which have a large ironcontent, can be roasted to a low sulfur content and then treated withadvantage by the present process while they are still hot from roasting.Some of the copper and nickel go forward with the ferric chlorid and canbe recovered from the residue delivered by the vaporizer but, for themost part, they are delivered as fixed chlorid with the gangue, whencethey may be extracted by leaching. Certain titaniferous iron ores mayalso be advan- -tageously treated by the present process,

yielding a titanium concentrate as a useful product. Where these orescontain vana dlum, as they often do, the vanadium is also placed incondition for easy recovery.

As shown, the ferric chlorid vapors leave the reaction chamber and passpractically directly to the ferric chlorid condenser. But, if desired,they may 0 through intermediate dust settling'cham ers of iron linedwith brick or ceramic material to settle out the bulk of the dust prior'to condensing the ferric chlorid. In so doing, the gases may be cooledto approximately 300 C. prior to entering the condenser. In thecondenser it is advantageous so to operate that the gases pass slowlydownward with as little stirring as is consistent with keeping the wallsclear. It is better to obtain the condensate more on the walls than as afog of suspended particles; i. e., I desire to obtain, so'to speak, anannular cooling of the downward passing prism of vapors and gases ratherthan any convectional cooling which would result in the formation of afog of fine particles.

The use of very fine iron oxid crystallized from aerial suspension asmicaceous particles as a filler for rubber is advantageous.

' What I claim is: I

1. In the removal and recovery of iron oxid from materials containingthe same, the cyclicprocess which comprises treating a materialcontaining iron oxid with chlorin under reducing conditions to produceferric chlorid, treating the produced ferric chlorid in vapor form withair to reform ferric oxid and chlorin, and returning the chlorin toserve anew.

2. In the removal and recovery of iron oxid from materials containingthe same, the process which comprises heating a material containing ironoxid in the presence of chlorid under reducing conditions to producevapors of ferric chlorid, coolin the;

efliuent gases and vapors to condense ferric chlorid therefrom,revaporizing such ferric chlorid, contacting the vapors with hot air toreform ferric oxid and chlorin, and returning the chlorin for reuse.

3. In the manufacture of chlorin for industrial purposes, the processwhich comprises vaporlzing ferric chlorid, admixin with air at atemperature around 800 C. an separating and removing the iron oxidproduced.

4. In the manufacture of chlorin for in-- dustrial purposes, the processwhich comprises vaporizing ferric chlorid, burning the vapors withoxygen at about 800 C. and

removing the oxid of iron formed.

5. The process of removing and recovering iron oxid from low grade ironores contaming oxid which comprises treating such an iron ore withchlorin and carbon to produce vapors of ferric chlorid, condensing thevapors of ferric chlorid, revaporizing and oxidizing the vapors with hotair to produce chlorin and oxid of iron.

6. In the treatment of iron ores containingiron oxidand other values,the process which comprises chlorinating such an ore under reducingconditions to produce vapors of ferric chlorid, removing and condensingthe ferric chlorid vapors, revaporizing the ferric chlorid andrecovering other chlorids from the volatilization residues and oxidizingthe ferric chlorid in vapor form with air to reproduce chlorinandironoxid.

7. The process of removing and recovering iron oxid which comprisestreating material containing the same with chlorin under reducingconditions at a temperature around 450 C. to produce vapors of ferricchlorid and burning said ferric chlorid in a vapor form and at atemperature of 700 to 800 C.

-with oxygen to reproduce the chlorin and densing and revaporizing to reain dust and fixed chlorids and burning t e vaporized [chlorid toreproduce chlorin and iron oxid.

9. In the removal and recovery of iron oxid from materials containingthe same the process which comprises producing ferric chlorid from suchoxid and burmng said 5 ferric chloridwith oxygen at a temperature around800 0., the reacting materials being kept at the combustion temperaturefor a period of time of the order of 3 to 12 seconds to produce a finegrained oxid.

10. In the recovery of iron oxid from ferric chlorid the process whichcomprises leading va rs of ferric chlorid together with hea air into aroomy reaction chamber at a temperature in the neighorhood of 15 800" O.and gravitally'aeparatmg the fine iron oxid produced from thechlorin-containin gas.

the treatment of materials containin iron oxid as well as other heavymetal va ues, the process which comprises removing the iron oxid fromsuch a material by treatment with chlorin under reducin conditions at atemperature around 45 0., removing the vapors of ferric chloridproduced, recoverin the fixed metal chlorids also produced an burningthe ferric chlorid in the vapor form to reproduce chlorin' and ironoxid.

f In testimony whereof I have hereunto affixed my signature.

ERNEST w. wEsco'rr.

